Helicopters are often equipped with so-called helicopter search lights. Such helicopter search lights are provided for illuminating the environment of the helicopter, in particular for illuminating the ground in an area in front of and below the helicopter. Helicopter search lights are particularly used for inspecting the ground for potential obstacles, such as power lines, tress, etc., in particular during a landing approach.
The result of operating currently available helicopter search lights is not satisfactory under all environmental conditions: When using the helicopter search light, the brightness, i.e. the luminance measured in cd/m2, of the ground, as it is seen by the pilot, can change by some orders of magnitude within fractions of a second. This may happen due to different ground scenarios, such as forests, water, streets, snow covered areas etc., as well as due to sudden changes of the distance between the helicopter and the illuminated objects, e.g. when flying in a downtown area with high buildings in between. Due to the adaptation delay of the human eye such a fast change of the luminance may cause temporary loss of sight of the pilot. This not only is inconvenient for the pilot, but may also result in dangerous situations.
Accordingly, it would be beneficial to provide a helicopter search light that is capable of providing improved illumination in particular under changing environmental conditions.